A method for preparing a composite mask for high-energy ion implantation

Abstract

The invention discloses a preparation method of a composite mask for high-energy ion implantation. The mask is a composite photoresist mask with a three-layer structure, a photoresist mask figure of the composite mask is made between an implantation barrier layer dielectric film and a surface layer sacrifice dielectric film, and is used for high-energy ion implantation of the mask. The preparation method comprises the steps that the mask figure is formed on the surface of the implantation barrier layer dielectric film through positive photoresist in a photoetching mode, and the surface layer sacrifice dielectric film grows in an injection region, and the side wall and the top end of the photoresist mask through a positive and negative inclination film evaporation technology, and is used for high-energy ion implantation. The composite mask can solve the problem that the photoresist mask chaps and denatures under the high-energy ion bombardment, no residue is left when the mask is removed, the surface cleanliness of a chip is guaranteed, and device performance is improved.

Description

technical field [0001] The invention relates to mask technology in microelectronic technology, in particular to a method for preparing a composite mask used for HgCdTe high-energy ion implantation. Background technique [0002] Infrared focal plane array detectors based on mercury cadmium telluride photodiodes have been widely used in military security, resource exploration, ocean monitoring, and space remote sensing. According to the device structure, HgCdTe photodiodes can be divided into n-on-p type and p-on-n type. The n-on-p process has matured after decades of technology accumulation, and the short-wave infrared (SWIR) and mid-wave infrared (MWIR) HgCdTe FPA devices based on this process have already had high performance. However, for long-wave (LW) and very long-wave (VLW) devices, in order to obtain the spectral response of the corresponding band, the band gap of the HgCdTe base material must be further reduced (<90meV). In such a narrow bandgap, the tunneling c...

AI Technical Summary

Problems solved by technology

Although the hard mask avoids the bombardment denaturation and residual problems of the photoresist mask, it needs to deposit an additional dielectric film, and perform multi-step photolithography and etching, and the process is complex

The reasons why the hard mask is not suitable for HgCdTe devices are: 1) The deposition temperature of the hard mask layer is far beyond the temperature range (below 70°C) that the HgCdTe material can withstand, while the low temperature growth (2 , graphite, amorphous carbon, etc.) have a large lattice mismatch with HgCdTe materials, and the adhesion of the film is poor; 3) the hard mask requires multi-step photolithography and pattern etching, and the introduced pattern size There are many process errors, which makes it difficult to guarantee the pattern accuracy of the small-size implantation area

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